This invention relates generally to solenoid valves. More specifically it relates to a means for separably attaching a solenoid to a valve which provides for secure retention of the two in assembly, yet allows the two to be readily separated for disassembly.
The invention arises in the context of a solenoid valve assembly in which the solenoid and the valve body are axially fitted together, and the valve body forms a part of the magnetic circuit. In a solenoid valve assembly of this type where the axial extent of the fit between the solenoid and the valve body is limited, a problem may arise if there is insufficient space to provide for both the magnetic circuit and the mechanical attachment of the solenoid to the valve body. The present invention is directed to a construction that provides a solution for this problem. The construction that embodies the present invention also is capable of providing a sufficiently high resistance to the solenoid being pulled apart from the valve body, yet provides the capability for easy disassembly of one from the other when disassembly is intended.
Briefly, the invention comprises a construction in which a solenoid has a magnetically conductive cylindrical housing that is fitted over a cylindrical axial surface of the valve body. The housing has an axial slot running along its entire length that allows the housing to be resiliently circumferentially expanded. The cylindrical housing is sized to circumferentially grip the cylindrical axial surface of the valve body and the axial extent the cylindrical axial surface of the valve body is long enough to provide an adequate space for the magnetic flux passing between the solenoid and the valve body. The valve body is provided with a narrow cylindrical groove immediately behind its cylindrical axial surface. The cylindrical housing of the solenoid has a plurality of discrete radially inwardly directed stakes formed at the end edge of the housing and these stakes fit into the narrow groove in the valve body so as to be in an interference relationship with a shoulder that exists between the cylindrical axial surface of the valve body and the groove in the valve body. The construction provides more than adequate retention of the solenoid on the valve body yet when it is desired to separate the two, such separation may be easily preformed in the following manner. A tool such as a screwdriver is inserted into the axial slot in the cylindrical housing of the solenoid and rotated to slightly circumferentially expand the housing. This expansion enables the solenoid to be pulled axially off the valve body with a much lower force than the normal assembled retention force. The ability to separate the solenoid from the valve assembly is desirable for repair operations. Reassembly of the solenoid to the valve body is accomplished by aligning the two parts and pushing them together. During this process the housing of the solenoid in effect snaps onto the valve body.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.